Reception device and transmission device

ABSTRACT

In a case of a contention-based radio communication technique, it is necessary to identify a terminal apparatus that has performed data transmission among terminal apparatuses sharing a frequency resource. There is a problem that it is difficult to identify the terminal apparatus that has performed data transmission in a case with a large number of terminal apparatuses that are non-orthogonally spatial multiplexed. Included are: a reception processing unit possible to perform first data reception of receiving a data signal transmitted without SR reception and control information of transmission permission and second data reception of receiving a data signal transmitted after SR reception or transmission of control information of transmission permission; an identification signal separator configured to separate an identification signal; a transmission terminal identification unit configured to identify the transmission device, based on the identification signal; a control information transmitting unit configured to transmit in advance a transmission parameter; and a reference signal separator configured to separate a DMRS. The transmission terminal identification unit identifies the transmission device, based on the identification signal only in the first data reception, and the reference signal separator separates the DMRS only in the second data reception.

TECHNICAL FIELD

The present invention relates to a reception device and a transmissiondevice.

BACKGROUND ART

In recent years, the Fifth Generation mobile telecommunication systems(5G) has been attracting attention, and standardization of communicationtechnologies to enable Massive Machine Type Communications (mMTC) mainlyby a number of terminal apparatuses, Ultra-reliable and low latencycommunications, and Enhanced mobile broadband is expected. Inparticular, future implementation of the Internet of Things (IoT) invarious apparatuses is expected, and one of key elements of 5G isimplementation of mMTC.

For example, in the 3rd Generation Partnership Project (3GPP), aMachine-to-Machine (M2M) communication technique has been standardizedas Machine Type Communication (MTC), in which terminal apparatusesperforming small-sized data transmission and/or reception areaccommodated (NPL 1). Moreover, standardization of Narrow Band-IoT(NB-IoT) is also being advanced to support low-rate data transmission ina narrow band.

In the Long Term Evolution (LTE), the LTE-Advanced, the LTE-AdvancedPro, and the like, that have been standardized by the 3GPP, a terminalapparatus transmits Scheduling Request (SR) upon occurrence of trafficof transmission data, and, after reception of control information oftransmission permission (UL Grant) from a base station apparatus, andperforms the data transmission using a transmission parameter in thecontrol information included in the UL Grant, at prescribed timing. Aradio communication technique in which a base station apparatus performsradio resource control of all uplink data transmissions (datatransmissions from terminal apparatuses to the base station apparatus)as described above has been implemented. With this technique, the basestation apparatus enables Orthogonal Multiple Access (OMA) using radioresource control, which makes it possible to perform uplink datareception by simple reception processing.

However, in such a known radio communication technique, since the basestation apparatus performs the entire radio resource control,transmission and/or reception of control information is needed beforedata transmission irrespective of the amount of data to be transmittedfrom a terminal apparatus. This in particular leads to a relativeincrease of the proportion of control information with a decrease insize of data to transmit. In a case that a terminal performstransmission of small-sized data, it is effective, from the viewpoint ofoverhead relating to control information, to use a contention-based(Grant Free) radio communication technique, in which a terminalapparatus performs data transmission without SR transmission andreception of any UL Grant transmitted from a base station apparatus.Moreover, in such a contention-based radio communication technique, timefrom data occurrence to data transmission can be reduced.

CITATION LIST Non-Patent Literature

-   NPL 1: 3GPP, TS22.368 V11.6.0, “Service requirements for    Machine-Type communications (MTC)”, September 2012

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

However, in a case that a number of terminal apparatuses perform uplinkdata transmission using the contention-based radio communicationtechnique, it is assumed that multiple terminal apparatuses share afrequency resource, and this leads to a problem that data signals of themultiple terminal apparatuses collide with each other at the same timeand the same frequency. Even in a case that data signals collide witheach other at the same time and the same frequency, and data fromterminal apparatuses the number of which is greater than the number ofreceive antennas of a base station is non-orthogonally spatialmultiplexed, transmission data signals can be detected by the basestation apparatus applying turbo equalization, Successive InterferenceCanceller (SIC), or Symbol Level Interference Canceller (SLIC) toreception processing. In a case of the contention-based radiocommunication technique, however, it is necessary to identify a terminalapparatus that has performed data transmission among terminalapparatuses sharing a frequency resource. In particular, there is aproblem that it is difficult to identify a terminal apparatus that hasperformed data transmission in a case with a large number of terminalapparatuses that are non-orthogonally spatial multiplexed.

The present invention has been made in view of the above-describedrespects, and is to provide a communication method that enables a basestation apparatus to identify a terminal apparatus that has performeddata transmission in a case that a number of terminal apparatusesperform uplink data transmission using a contention-based radiocommunication technique.

Means for Solving the Problems

(1) The present invention has been made to solve the above-describedproblem, and an aspect of the present invention is a reception devicefor receiving a data signal from each of multiple transmission devices,the reception device including: a reception processing unit configuredto perform first data reception of receiving the data signal transmittedwithout scheduling request reception and transmission of controlinformation of transmission permission and second data reception ofperforming the scheduling request reception and transmission of thecontrol information of the transmission permission and receiving thedata signal transmitted based on the control information; anidentification signal separator configured to separate, from anorthogonal resource, an identification signal received together with thedata signal; a transmission terminal identification unit configured toidentify, based on the identification signal, the transmission devicethat has performed data transmission; a control information transmittingunit configured to transmit in advance a transmission parameter to beused for the data transmission; and a reference signal separatorconfigured to separate a demodulation reference signal. The transmissionterminal identification unit identifies the transmission device, basedon the identification signal transmitted based on the transmissionparameter, only in a case of performing the first data reception. Thereference signal separator separates the demodulation reference signalonly in a case of performing the second data reception.

(2) In an aspect of the present invention, the control informationtransmitting unit transmits at least one of information on a subframepossible to perform the first data transmission, the information beingspecific to the transmission device, and information on a frequencyresource, the information being specific to the transmission device.

(3) In an aspect of the present invention, the control informationtransmitting unit transmits, for each of the transmission devices,control information for each of a state possible to perform the firstdata transmission and a state impossible to perform the first datatransmission.

(4) An aspect of the present invention is a transmission device fortransmitting a data signal to a reception device, the transmissiondevice including: a transmission processing unit configured to transmitthe data signal without scheduling request transmission and reception ofcontrol information of transmission permission transmitted from thereception device; an identification signal multiplexing unit configuredto multiplex an identification signal to an orthogonal resource; and acontrol information receiving unit configured to receive in advance atransmission parameter relating to transmission of the data signal. Thetransmission processing unit transmits the identification signal and adata signal together in a case of performing the data transmission basedon the transmission parameter.

(5) In an aspect of the present invention, the transmission parameterreceived by the control information receiving unit includes informationon a subframe possible to perform the data transmission, the informationbeing specific to the transmission device.

(6) In an aspect of the present invention, the transmission parameterreceived by the control information receiving unit includes informationon a frequency resource possible to perform the data transmission, theinformation being specific to the transmission device.

(7) In an aspect of the present invention, the transmission parameterreceived by the control information receiving unit includes informationon a state possible to perform the data transmission or a stateimpossible to perform the data transmission.

(8) In an aspect of the present invention, the transmission parameterreceived by the control information receiving unit includes informationon a cycle of a period of a state possible to perform the datatransmission and a period of a state impossible to perform the datatransmission.

Effects of the Invention

According to the present invention, a base station apparatus canidentify a terminal apparatus that has performed data transmission, in acase that a number of terminal apparatuses perform uplink datatransmission using a contention-based radio communication technique. Asa result of this, the base station apparatus can accommodate a number ofterminal apparatuses and reduce the amount of control information.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an example of a configuration of asystem according to a present embodiment.

FIG. 2 is a diagram illustrating an example of a sequence chart of datatransmission by a terminal apparatus according to a known radiocommunication technique.

FIG. 3 is a diagram illustrating an example of a sequence chart of datatransmission by a terminal apparatus according to a radio communicationtechnique of the present embodiment.

FIG. 4 is a diagram illustrating an example of an uplink frame structureaccording to the known radio communication technique.

FIG. 5 is a diagram illustrating an example of an uplink frame structureaccording to the radio communication technique of the presentembodiment.

FIG. 6 is a diagram illustrating an example of a configuration of theterminal apparatus according to the present embodiment.

FIG. 7A is a diagram illustrating an example of a configuration of atransmit signal generation unit 103 according to the present embodiment.

FIG. 7B is a diagram illustrating an example of the configuration of thetransmit signal generation unit 103 according to the present embodiment.

FIG. 7C is a diagram illustrating an example of the configuration of thetransmit signal generation unit 103 according to the present embodiment.

FIG. 8 is a diagram illustrating an example of the configuration of thetransmit signal generation unit 103 according to the present embodiment.

FIG. 9 is a diagram illustrating an example of a configuration of asignal multiplexing unit 104 according to the present embodiment.

FIG. 10 is a diagram illustrating an example of a configuration of abase station apparatus according to the present embodiment.

FIG. 11 is a diagram illustrating an example of a configuration of asignal separator 205-1 according to the present embodiment.

FIG. 12 is a diagram illustrating an example of a configuration of asignal detection unit 206 according to the present embodiment.

FIG. 13 is a diagram illustrating an example of a configuration ofidentification signals of transmission terminal apparatuses according tothe present embodiment.

FIG. 14 is a diagram illustrating an example of identification signalsand data transmissions of the terminal apparatuses according to thepresent embodiment.

FIG. 15A is a diagram illustrating an example of an uplink framestructure according to the radio communication technique of the presentembodiment.

FIG. 15B is a diagram illustrating an example of the uplink framestructure according to the radio communication technique of the presentembodiment.

FIG. 16 is a diagram illustrating an example of the uplink framestructure according to the radio communication technique of the presentembodiment.

FIG. 17 is a diagram illustrating an example of a sequence chart of datatransmission by the terminal apparatus according to the radiocommunication technique of the present embodiment.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments will be described with reference to thedrawings. In each embodiment below, a description will be given byassuming, based on Machine-to-Machine Communication (M2M communication)(also referred to as Machine Type Communication (MTC), communication forInternet of Things (IoT), and Narrow Band-IoT (NB-IoT)), that atransmission device is a MTC terminal (referred to as a terminalapparatus below) and a reception device is a base station apparatus.Note that, however, the disclosure is not limited to the above exampleand is also applicable to uplink transmission in a cellular system. Inthis case, a terminal apparatus configured to perform data transmissioninvolving human is a transmission device, and a base station apparatusis a reception device. Furthermore, it is also applicable to downlinktransmission in a cellular system. In this case, transmission andreception devices in data transmission are reversed to those in uplinktransmission. In addition, it is also applicable to Device-to-Device(D2D) communication. In this case, both a transmission device and areception device are terminal apparatuses.

FIG. 1 illustrates an example of a configuration of a system accordingto the present embodiment. The system includes a base station apparatus10 and terminal apparatuses 20-1 to 20-Nm. Note that the number ofterminal apparatuses (terminals, mobile terminals, mobile stations, orUser Equipment (UE)) is not limited to any, and the number of antennasof each apparatus may be one or multiple. The base station apparatus 10may perform communication using a so-called licensed band with a licenseissued from a country or a region for providing services by a radiooperator, or may perform communication using a so-called unlicensed bandrequiring no license from the country or the region. The base stationapparatus 10 may be a macro base station apparatus with a large coverageor a small-cell base station or a pico base station apparatus (alsoreferred to as a Pico evolved Node B (eNB), Small cell, Low Power Node,or a Remote Radio Head) with a coverage smaller than that of the macrobase station apparatus. Each frequency band other than a licensed bandis not limited to the example of an unlicensed band herein and mayalternatively be a white band (white space) or the like. The basestation apparatus 10 may employ a Carrier Aggregation (CA) techniqueusing multiple Component Carriers (CCs) (also referred to as Servingcells) in a band used in LTE communication, or may perform datatransmission on different CCs or may perform data transmission on thesame CC for MTC and communication different from MTC. As an example ofemploying CA, communication different from MTC may be assumed to use aPrimary cell (PCell), and MTC communication may be assumed to use aSecondary cell (SCell). Alternatively, different subcarriers may be usedfor MTC and communication different from MTC in the same CC.

The terminal apparatuses 20-1 to 20-Nm is assumed to be able to transmitdata in MTC to the base station apparatus 10. Each of the terminalapparatuses 20-1 to 20-Nm receives, at the time when the terminalapparatus has established a connection with a base station, controlinformation necessary for data transmission from the base stationapparatus 10 or another base station apparatus in advance. Afteroccurrence of data to transmit (traffic), a corresponding one of theterminal apparatuses 20-1 to 20-Nm performs data transmission by using aradio communication technique (also referred to as a contention-basedradio communication technique, Grant free access, Grant freecommunication, Grant free data transmission, or the like) having no needof Scheduling Request (SR) transmission or reception of transmissionpermission control information (UL Grant) transmitted from the basestation apparatus. However, in a case that a radio communicationtechnique (also referred to as a non-contention-based radiocommunication technique, Grant-based access, Grant-based communication,Grant-based data transmission, or the like; hereinafter referred to as anon-contention-based radio communication technique), such as the LongTerm Evolution (LTE), the LTE-Advanced, or the LTE-Advanced Pro, whichrequires SR transmission and/or UL Grant reception, can also be used,each of the terminal apparatuses 20-1 to 20-Nm may switch thecontention-based radio communication technique and thenon-contention-based radio communication technique according totransmission data, data size, Quality of Service (QoS) of thetransmission data, and/or the like, to use a corresponding radiocommunication technique. In other words, each of the terminalapparatuses 20-1 to 20-Nm may determine whether to perform datatransmission using a radio resource scheduled by the base stationapparatus through SR transmission before the data transmission or toperform data transmission by using at least part of a radio resourceprescribed before the occurrence of data. The QoS may include thereliability of data transmission, delay time for data transmission, orcommunication rate, and may also include an indicator for powerconsumption relating to data transmission of the terminal apparatus(e.g., power per bit in the data transmission) or the like. Here, theterminal apparatuses 20-1 to 20-Nm are not limited only to MTC but mayalso be capable of Human-to-Machine (H2M) Communication and/orHuman-to-Human (H2H) Communication involving human, or the like. Inthese cases, the base station apparatus 10 may transmit UL Grant, whichis control information including a transmission parameter to be used fordata transmission on a Physical Downlink Control CHannel (PDCCH), anEnhanced PDCCH (EPDCCH), or a physical channel on which another downlinkcontrol information is transmitted, through dynamic scheduling orSemi-Persistent Scheduling (SPS) depending on data type. Thecorresponding one of the terminal apparatuses 20-1 to 20-Nm performsdata transmission, based on the transmission parameter in the UL Grant.

First Embodiment

FIG. 2 illustrates an example of a sequence chart of data transmissionby a terminal apparatus according to a known radio communicationtechnique. The base station apparatus transmits configuration controlinformation upon establishment of a connection with a terminal apparatus(S100). The configuration control information may be notified throughRadio Resource Control (RRC) or may be higher layer control information,such as System Information Block (SIB) or a DCI format. A physicalchannel to be used is a PDCCH, an EPDCCH, or a Physical Downlink SharedCHannel (PDSCH) or another physical channel may be used. In a case thatthe terminal apparatus has not received any UL Grant at the time whenuplink data occurs, the terminal apparatus transmits SR to request an ULGrant (S101). After receiving the SR, the base station apparatustransmits an UL Grant to the terminal apparatus on the PDCCH or theEPDCCH (S102). In a case of Frequency Division Duplex (FDD; alsoreferred to as frame structure type 1), the terminal apparatus performsdata transmission based on the transmission parameter included in the ULGrant, in the subframe that is 4 msec after the subframe in which the ULGrant is detected through blind decoding on the PDCCH or the EPDCCH(S103). Note that although the interval is not limited to 4 msec in acase of Time Division Duplex (TDD; also referred to as frame structuretype 2), the description is given based on FDD to make explanationsimple. The base station apparatus detects data transmitted from theterminal apparatus and transmits ACK/NACK indicating whether the datadetected in the subframe that is 4 msec after the subframe in which thedata signal has been received involves any error (S104). Here, in S101,in a case that no SR transmission resource is notified through RRC, theterminal apparatus requests UL Grant by using a Physical Random AccessCHannel (PRACH). Moreover, it is assumed that, in S102, datatransmission of only one subframe is possible in a case of dynamicscheduling; periodic data transmission is allowed in a case of SPS andinformation, such as SPS period, is notified through RRC in S100. Theterminal apparatus stores the transmission parameter, such as SRtransmission resource, the SPS period, and/or the like notified from thebase station apparatus through the RRC.

FIG. 3 illustrates an example of a sequence chart of data transmissionby a terminal apparatus according to a radio communication technique ofthe present embodiment. First, the base station apparatus transmitsconfiguration control information upon establishment of a connectionwith a terminal apparatus (S200). The configuration control informationmay be notified through RRC, or may be higher layer control information,such as SIB or a DCI format. A physical channel to be used may be thePDCCH, the EPDCCH, or the PDSCH, or may use another physical channel.The configuration control information includes radio resources,transmission parameters, and the like to be used in a contention-basedradio communication technique. In a case that the terminal apparatus canalso use a non-contention-based radio communication technique, such asthe LTE, the LTE-Advanced, and/or the LTE-Advanced Pro, theconfiguration control information may also include control informationnotified in S100 in FIG. 2. In a case that the terminal apparatus hasreceived the control information in S200 upon occurrence of uplink data,the terminal apparatus transmits the data by using the contention-basedradio communication technique, which does not require SR transmissionand reception of UL Grant transmitted from the base station apparatus(S201-1). Here, the terminal apparatus has been notified, in S200, ofthe number of transmissions, the transmission period, and/or thetransmission period of the same data, a radio resource to be used forthe transmission, a transmission parameter, and/or the like, accordingto the required QoS (reliability of the data transmission, delay time ofthe data transmission, and/or the communication rate may also beincluded), and transmits data similar to that in S201-1, based on thecontrol information received in S200 (S201-2 to S201-L). Note that,however, the present invention is not limited to a case of transmittingthe same data multiple times, and data may be transmitted only once bysetting L=1. The base station apparatus detects data transmitted fromthe terminal apparatus and transmits ACK/NACK indicating whether or notthe data detected in the subframe that is X msec after the subframe inwhich the data signal has been received involves any error (S202). X maybe set at X=4 from data transmission as in the known FDD or may take adifferent value. Although the last data transmission (S201-L) is used asa reference in FIG. 3, the reference is not limited to this example. Forexample, a subframe in which the base station apparatus has successfullydetected data without any error may be used as a reference, and thetransmission may be performed in the subframe X msec after thissubframe. In the contention-based radio communication technique,ACK/NACK may not necessarily be transmitted, and the base station mayswitch whether or not to transmit ACK/NACK depending on used techniqueamong the non-contention-based and contention-based radio communicationtechnique.

FIG. 4 illustrates an example of an uplink frame structure according tothe known radio communication technique. In the known uplink framestructure, one frame is 10 msec and is configured of 10 subframes, onesubframe is configured of two slots, and one slot is configured of sevenOFDM symbols. A De-Modulation Reference Signal (DMRS) is mapped to theOFDM symbol in the middle of each slot, that is, OFDM symbol #4 in acase that there are OFDM symbols #1 to #7. Moreover, in the knowntechnique, in a case that the terminal apparatus receives UL Grant insubframe #1, data transmission is possible in subframe #5, which is 4msec after subframe #1. FIG. 5 illustrates an example of an uplink framestructure according to the radio communication technique of the presentembodiment. FIG. 5 is an example of a case of using the contention-basedradio communication technique by assuming that the frame structure issimilar to that in FIG. 4. In the contention-based radio communicationtechnique, the terminal apparatus can perform data transmissionimmediately after occurrence of data. In a case that data occurs beforesubframe #1, the terminal apparatus performs data transmissionillustrated in the example in FIG. 5. A transmission terminalidentification signal is transmitted in subframe #1, and data istransmitted in subframe #2. The transmission terminal identificationsignal and a data transmission method will be described later in detail.

FIG. 6 illustrates an example of a configuration of the terminalapparatus according to the present embodiment. Note that the minimumnumber of blocks necessary for the present invention are illustrated. Adescription will be given on the assumption that the terminal apparatuscan use both the contention-based radio communication technique and thenon-contention-based radio communication technique, which is theabove-described known technique, for MTC data transmission as theterminal apparatuses 20-1 to 20-Nm. However, the present invention isalso applicable to a case in which the terminal apparatus can use onlythe contention-based radio communication technique. In this case, noprocessing relating to the non-contention-based radio communicationtechnique exists, but the basic configuration is similar to this. Theterminal apparatus receives control information transmitted from thebase station apparatus on the EPDCCH, the PDCCH, or the PDSCH, via thereceive antenna 110. The radio receiving unit 111 downconverts areceived signal to a signal of a baseband frequency, performsAnalog/Digital (A/D) conversion on a resultant signal, and inputs, to acontrol information detection unit 112, a signal obtained by removing aCyclic Prefix (CP) from an obtained digital signal. The controlinformation detection unit 112 detects a Downlink Control Information(DCI) format transmitted on the PDCCH or the EPDCCH and destined to theterminal apparatus itself, through blind decoding. In the blinddecoding, decoding processing is performed on a Common Search Space(CSS) or a UE-specific Search Space (USS) that is a candidate to whichthe DCI format is mapped, to detect control information. Here, multipleformats are defined for the DCI format for different uses, and uplinksingle antenna DCI format 0, Multiple Input Multiple Output (MIMO) DCIformat 4, and the like are defined, for example. The control informationdetection unit 112 also performs detection in a case of receiving an RRCsignal. The control information detection unit 112 inputs the detectedcontrol information to a transmission parameter storage unit 113. In acase of receiving UL Grant, such as dynamic scheduling or SPS, thetransmission parameter storage unit 113 inputs the control informationto a traffic management unit 114. In a case of receiving configurationcontrol information through RRC, the transmission parameter storage unit113 holds the control information until data transmission using thecontention-based radio communication technique. The configurationcontrol information held by the transmission parameter storage unit 113will be described later in detail.

In a case that a bit sequence of transmission data is input, the controlinformation is input upon reception of UL Grant, and the configurationcontrol information for the contention-based radio communicationtechnique has been received in advance, these pieces of controlinformation are also input to the traffic management unit 114. The type,QoS, and the like of transmission data may also be input to the trafficmanagement unit 114. The traffic management unit 114 selects to use thecontention-based or the non-contention-based radio communicationtechnique, based on the input information, inputs the transmissionparameter corresponding to the selected radio communication technique,to an error correction coding unit 101, a modulating unit 102, atransmit signal generation unit 103, a signal multiplexing unit 104, andan identification signal generation unit 115, and inputs a data bitsequence to the error correction coding unit 101.

The error correction coding unit 101 performs coding with errorcorrection code on the input data bit sequence. As the error correctioncode, turbo code, Low Density Parity Check (LDPC) code, convolutionalcode, Polar code, or the like is used, for example. The type of errorcorrection code and the coding rate used by the error correction codingunit 101 may be determined by a transmission and/or reception device inadvance, may be input from the traffic management unit 114, or may beswitched depending on the used technique among the contention-based andnon-contention-based radio communication technique. In a case that thekind of error correction code and the coding rate are notified ascontrol information, these pieces of information are input from thetraffic management unit 114 to the error correction coding unit 101. Theerror correction coding unit 101 may perform puncturing or interleavingon the coding bit sequence according to the coding rate to apply. In acase of performing interleaving on the coding bit sequence, the errorcorrection coding unit 101 performs interleaving for configuring adifferent sequence for each terminal apparatus. The error correctioncoding unit 101 may apply scrambling. Application of scrambling may beallowed only in a case that a scrambling pattern used by each terminalapparatus can be uniquely identified by using an identification signalto be described later.

The modulating unit 102 receives an input of information on a modulationscheme from the traffic management unit 114 and performs modulation on acoding bit sequence input from the error correction coding unit 101, tothereby generate a modulation symbol sequence. The modulation scheme is,for example, Quaternary Phase Shift Keying (QPSK), 16-ary QuadratureAmplitude Modulation (16 QAM), 64 QAM, 256 QAM, or the like.Alternatively, the modulation scheme may not necessarily be Graylabeling, and set partitioning may be used. Gaussian Minimum-ShiftKeying (GMSK) may be used. The modulating unit 102 outputs the generatedmodulation symbol sequence to the transmit signal generation unit 103.Here, the modulation scheme or the modulation method may be determinedby the transmission and/or reception device in advance, may be inputfrom the traffic management unit 114, or may be switched depending onthe used technique among the contention-based and non-contention-basedradio communication technique.

FIGS. 7A to 7C illustrate examples of a configuration of the transmitsignal generation unit 103 according to the present embodiment. In FIG.7A, a DFT unit 1031 performs discrete Fourier transform on inputmodulation symbols to transform a time domain signal to a frequencydomain signal, and then outputs the obtained frequency domain signal toa signal assignment unit 1032. The signal assignment unit 1032 receivesResource allocation information, which is information of one or moreResource Blocks (RBs) to be used for data transmission, from the trafficmanagement unit 114 and assigns the frequency-domain transmit signal tothe specified RB(s). The resource allocation information input from thetraffic management unit 114 is notified through UL Grant in a case ofthe non-contention-based radio communication, while being notified inadvance through configuration control information in a case of thecontention-based radio communication technique. Here, one RB is definedby 12 subcarriers and one slot (seven OFDM symbols), and the resourceallocation information is information for allocating one subframe (twoslots). In the LTE, one subframe is defined as 1 msec, and eachsubcarrier interval is defined as 15 kHz. However, the time period ofone subframe and the subcarrier interval may vary, for example, 2 msecand 7.5 kHz, 0.2 msec and 75 kHz, 0.1 msec and 150 kHz, and the like,and resource allocation information may be notified by the unit of onesubframe even in a different frame structure. The resource allocationinformation may be for notification of allocation of multiple subframesirrespective of a case of having a similar subframe structure to that ofthe LTE or a case of having a different subframe structure from that ofthe LTE, may be for notification of allocation by slot, may be fornotification of allocation by the unit of OFDM symbol, or may be fornotification of allocation by the unit of two OFDM symbols. The resourceallocation information may be, instead of by RB, by the unit of onesubcarrier, by Resource Block Group (RBG) configured of multiple RBs, ormay be for allocation of one or more RBGs.

In FIG. 7B, a phase rotation unit 1030 performs phase rotation on inputmodulation symbols. For the phase rotation performed on a time-domaindata signal in the phase rotation unit 1030, a pattern input from thetraffic management unit 114 is used to apply a different pattern foreach terminal apparatus. Examples of the phase rotation pattern are apattern for performing different phase rotation for each modulationsymbol and the like. The phase rotation pattern input from the trafficmanagement unit 114 is assumed to be shared by the terminal apparatusand the base station apparatus by being notified through UL Grant, beingnotified through configuration control information in advance, or thelike. The DFT unit 1031 and the signal assignment unit 1032 are similarto those in FIG. 7A, and hence descriptions thereof are omitted. Here,although the example in which phase rotation is performed on atime-domain data signal is illustrated in FIG. 7B, similar effects maybe obtained in a different method. For example, a different cyclic delaymay be set to a frequency-domain signal obtained by the DFT unit 1031,for each terminal apparatus. Specifically, assume that frequency-domainsignals of the terminal apparatus 20-u with no cyclic delay are SU(1),SU(2), SU(3), and SU(4). In this case, cyclic delay with a delay amountof one symbol is set for the terminal apparatus 20-i to obtain Si(4),Si(1), Si(2), and Si(3), for example.

The DFT unit 1031 and the signal assignment unit 1032 in FIG. 7C aresimilar to those in FIG. 7A, and hence descriptions thereof are omitted.A phase rotation unit 1033 performs phase rotation on thefrequency-domain data signal obtained by the DFT unit 1031. For thephase rotation performed on the frequency-domain data signal in thephase rotation unit 1033, a pattern input from the traffic managementunit 114 is used to apply a different pattern for each terminalapparatus. Examples of the phase rotation pattern are one in whichdifferent phase rotation is performed for each frequency-domain datasignal, and the like. The phase rotation pattern input from the trafficmanagement unit 114 is assumed to be information shared by the terminalapparatus and the base station apparatus by being notified through ULGrant, being notified through configuration control information inadvance, or the like. Here, although the example in which phase rotationis performed on a frequency-domain data signal is illustrated in FIG.7C, similar effects may be obtained in a different method. For example,a different cyclic delay may be set to modulation symbols beforetransform to a frequency-domain signal by the DFT unit 1031, for eachterminal apparatus. Specifically, assume that frequency-domain signalsof the terminal apparatus 20-u with no cyclic delay are sU(1), sU(2),sU(3), and sU(4). In this case, cyclic delay with a delay amount of oneis set for the terminal apparatus 20-i to obtain si(4), si(1), si(2),and si(3), for example. Both the phase rotation unit 1030 and the phaserotation unit 1033 in FIG. 7B and FIG. 7C may be used. The transmitsignal generation unit 103 in each of FIGS. 7A to 7C inputs a transmitsignal to the signal multiplexing unit 104.

The configuration of the transmit signal generation unit 103 may be theconfiguration in FIG. 8. In this example, the transmit signal generationunit 103 performs interleaving on the modulation symbols input beforethe DFT unit 1031. In a case that interleaving is performed on themodulation symbols, interleaving for configuring a different sequencefor each terminal apparatus is performed.

FIG. 9 illustrates an example of a configuration of the signalmultiplexing unit 104 according to the present embodiment. The transmitsignal input from the transmit signal generation unit 103 is input to areference signal multiplexing unit 1041. Moreover, the trafficmanagement unit 114 inputs a parameter for generating a reference signalto a reference signal generation unit 1042 and inputs controlinformation to be transmitted to the base station apparatus, to acontrol information generation unit 1044. The reference signalmultiplexing unit 1041 multiplexes the input transmit signal and areference signal sequence (DMRS) generated by the reference signalgeneration unit. By thus multiplexing the transmit signal and the DMRS,the frame structure in FIG. 4 is generated. The frame structure in FIG.5 will be described later. Note that, in a case that the referencesignal is mapped to different OFDM symbols from the data signal as inthe frame structure in FIG. 4, the reference signal multiplexing unit1041 may multiplex the data signal and the reference signal in the timedomain.

Meanwhile, the control signal generation unit 1044 generates ChannelState Information (CSI), Scheduling Request (SR), andAcknowledgement/Negative Acknowledgement (ACK/NACK) of uplink controlinformation to be transmitted on the Physical Uplink Control CHannel(PUCCH) and outputs these to a control information multiplexing unit1043. The control information multiplexing unit 1043 multiplexes thecontrol information to the frame structure configured of the data signaland the reference signal. The signal multiplexing unit 104 inputs agenerated transmission frame to an IFFT unit 105. In a case that theterminal apparatus is not capable of transmitting the PUSCH and thePUCCH simultaneously, the terminal apparatus transmits only the signalwith high priority according to the priority levels of signalsdetermined in advance. Similarly in a case that the terminal apparatusis not capable of transmitting the PUSCH and the PUCCH simultaneouslydue to a lack of transmit power, the terminal apparatus transmits onlythe signal with high priority according to the priority levels ofsignals determined in advance. Different priority levels fortransmission of a signal may be assigned to a case of thecontention-based radio communication technique and thenon-contention-based radio communication technique. Alternatively, thepriority of the data to transmit exists, and according to the priority,the priority of the PUSCH may vary.

The IFFT unit 105 receives an input of a frequency-domain transmissionframe and performs inverse fast Fourier transform on each OFDM symbol,to thereby transform the frequency-domain signal sequence to thetime-domain signal sequence. The IFFT unit 105 inputs the time-domainsignal sequence to the identification signal multiplexing unit 106. Theidentification signal generation unit 115 generates a signal to transmitin a subframe for an identification signal in FIG. 5 and inputs thesignal to the identification signal multiplexing unit 106. Details ofthe identification signal will be described later. The identificationsignal multiplexing unit 106 multiplexes the time-domain signal sequenceand the identification signal to different subframes as in FIG. 5 andinputs a signal obtained through the multiplexing to a transmit powercontroller 107. Note that the identification signal multiplexing unit106 may multiplex the time-domain signal and the identification signalto different OFDM symbols or different slots of the same subframe. Thetransmit power controller 107 performs transmit power control by usingonly an open-loop transmit power control value or both open-loop andclosed-loop transmit power control values, and inputs the signalsequence after the transmit power control to a transmission processingunit 108. The transmit processing unit 108 inserts a CP into the inputsignal sequence, converts a resultant signal into an analog signalthrough Digital/Analog (D/A) conversion, and upconverts a signal afterthe conversion to a signal of a radio frequency to use for transmission.The transmission processing unit 108 amplifies a signal obtained throughupconversion by a Power Amplifier (PA) and transmits a signal after theamplification via a transmit antenna 109. The terminal apparatusperforms data transmission as described above. In a case that theterminal apparatus performs FIG. 7A in the transmit signal generationunit 103, this means that the terminal apparatus transmits a DiscreteFourier Transform Spread Orthogonal Frequency Division Multiplexing(DFTS-OFDM; also referred to as SC-FDMA) signal. In a case that theterminal apparatus performs FIG. 7B or FIG. 7C in the transmit signalgeneration unit 103, this means that the terminal apparatus transmits asignal obtained by applying phase rotation or cyclic delay to DFTS-OFDM.In a case that the terminal apparatus performs FIG. 8 in the transmitsignal generation unit 103, this means that the terminal apparatustransmits a DFTS-OFDM signal. In a case of a configuration that theterminal apparatus does not perform DFT in the transmit signalgeneration unit 103, i.e., the DFT unit 1031 does not exist in any ofFIGS. 7A to 7C and FIG. 8, this means that the terminal apparatustransmits an OFDM signal. The terminal apparatus may use theabove-described method, or may use a different spread method ordifferent transmit signal waveform generation method, in the transmitsignal generation unit 103.

FIG. 10 illustrates an example of a configuration of a base stationapparatus according to the present embodiment. According to FIG. 10, thebase station apparatus receives data transmitted from terminalapparatuses, at N receive antennas 201-1 to 201-N and inputs the data torespective receive antennas 202-1 to 202-N. The reception processingunits 202-1 to 202-N downconvert receive signals to signals of basebandfrequencies, perform A/D conversion on the resultant signals, and removeCPs from resultant digital signals. The reception processing units 202-1to 202-N output the respective signals obtained through the removal ofthe CPs to identification signal separators 203-1 to 203-N. Theidentification signal separators 203-1 to 203-N separate identificationsignals and other signals and output the identification signals to theidentification terminal identifying unit 211 and the other signals toFFT units 204-1 to 204-N. The transmission terminal identifying unit 211identifies the terminal apparatuses that have transmitted the data withreference to the identification signals to be described later andoutputs information on the transmission terminal apparatuses to achannel estimation unit 207 and signal separators 205-1 to 205-N. TheFFT units 204-1 to 204-N convert input receive signal sequences fromtime-domain signal sequences to frequency-domain signal sequencesthrough fast Fourier transform and output the obtained frequency-domainsignal sequences to the respective signal separators 205-1 to 205-N.

The signal separators 205-1 to 205-N all have a configuration in common,and FIG. 11 illustrates an example of a configuration of the signalseparator 205-1 according to the present embodiment. According to FIG.11, in the signal separator 205-1, a frequency-domain signal sequence isinput from the FFT unit 204-1 and information on the identifiedtransmission terminal apparatus is input from the transmission terminalidentifying unit 211, to a reference signal separator 2041. Thereference signal separator 2051 separates the frequency-domain signalsequence into a reference signal and other signals by using the inputinformation on the transmission terminal apparatus and outputs thereference signal to the channel estimation unit 207 and the othersignals to a control information signal separator 2052. The controlinformation separator 2052 separates the input signals into a controlsignal and a data signal and outputs the control signal to a controlinformation detection unit 2054 and a data signal to the assignmentsignal extraction unit 2053. The control information detection unit 2054detects a signal transmitted on the PUCCH and outputs, to a controlinformation generation unit 208, SR, CSI, and ACK/NACK to userespectively for uplink scheduling, downlink scheduling, andre-transmission control for downlink transmission. Meanwhile, theassignment signal extraction unit 2053 extracts a transmit signal foreach terminal apparatus, based on resource allocation informationnotified the terminal apparatus through control information.

The channel estimation unit 207 receives an input of De-ModulationReference Signal (DMRS), which is a reference signal transmitted bybeing multiplied with the data signal, and information on the identifiedtransmission terminal apparatus, estimates frequency response, andoutputs the frequency response estimated for demodulation to the signaldetection unit 206. In a case that a Sounding Reference Signal (SRS) isinput, the channel estimation unit 207 estimates frequency response tobe used for the next scheduling. The control information generation unit208 performs uplink scheduling and Adaptive Modulation and Coding (alsoreferred to as link adaptation), based on the frequency responseestimated based on the DMRS and/or SRS, generates a transmissionparameter to be used by the terminal apparatus for uplink transmission,and performs conversion to the DCI format. In a case that informationindicating whether or not the received data signal involves any error isinput from the signal detection unit 205, the control informationgeneration unit 208 generates control information for notification ofACK/NACK in the uplink transmission. Here, ACK/NACK in the uplinktransmission is transmitted on at least one of the Physical HARQ CHannel(PHICH), the PDCCH, and the EPDCCH. The control information transmittingunit 209 receives an input of control information obtained through theconversion by the control information generation unit 208, assigns theinput control information to the PDCCH and the EPDCCH, and transmits thecontrol information to each terminal apparatus.

FIG. 12 illustrates an example of a configuration of the signaldetection unit 206 according to the present embodiment. In the signaldetection unit 206, a cancellation processing unit 2061 receives inputsof the signals extracted by the signal separators 205-1 to 205-N of therespective terminal apparatuses. The cancellation processing unit 2061receives inputs of soft replicas from a soft replica generation unit2067 and performs cancellation processing on each receive signal. Anequalization unit 2062 generates equalization weights by using thefrequency response input from the channel estimation unit 207, based onthe MMSE principle and multiplies the signal obtained through the softcancellation by the equalization weights. The equalization unit 2062outputs the signals of the respective terminal apparatuses obtainedthrough the equalization to the respective IDFT units 2063-1 to 2063-U.The IDFT units 2063-1 to 2063-U convert receive signals obtained throughfrequency-domain equalization to time-domain signals. In a case that anyof the terminal apparatuses has performed cyclic delay, phase rotation,or interleaving on the signal before or after the DFT in transmissionprocessing, processing for restoring from cyclic delay, phase rotation,or the interleaving is performed on the receive signal obtained throughfrequency-domain equalization or the time-domain signal. Thedemodulation units 2064-1 to 2064-U receive inputs of information on amodulation scheme notified in advance or predetermined although notillustrated, perform demodulation processing on the receive signalsequences in time domain, to thereby obtain Log Likelihood Ratios (LLRs)in bit sequence, i.e., LLR sequences.

The decoding units 2065-1 to 2065-U receive inputs of information on acoding rate notified in advance or predetermined although notillustrated, perform demodulation processing on the LLR sequences. Here,to perform cancellation processing such as Successive InterferenceCanceller (SIC) or turbo equalization, the decoding units 2065-1 to2065-U output external LLRs or post LLRs of decoder outputs to thesymbol replica generation units 2066-1 to 2066-U. The difference betweenthe external LLRs and the post LLRs is whether or not to subtract priorLLRs to be input to the decoding units 2065-1 to 2065-U from therespective LLRs obtained through decoding. In a case that the terminalapparatuses have performed puncturing, interleaving, or scrambling on acoded bit sequence after error correction coding in transmissionprocessing, the signal detection unit 206 performs depuncturing(inserting 0 into the LLRs of bits obtained through puncturing),deinterleaving (restoring from interleaving), or descrambling on LLRsequences to be input to the decoding units 2065-1 to 2065-U. The symbolreplica generation units 2066-1 to 2066-U generate symbol replicas fromthe input LLR sequences according to the modulation schemes used by theterminal apparatuses for the data transmission and output the symbolreplicas to the soft replica generation unit 2067. The soft replicageneration unit 2067 transforms the input symbol replicas intofrequency-domain signals through DFT and assigns the signals to theresources used by the terminal apparatuses, to generate soft replicas bymultiplying the signals by frequency responses. In a case that thenumber of repetitions of SCI processing and/or turbo equalizationreaches a prescribed number of times, the decoding units 2065-1 to2065-U make hard decisions for the LLR sequences after the decoding,determine whether there is any error bit through Cyclic Redundancy Check(CRC), and outputs information indicating whether or not there is anyerror bit to the control information generation unit 208.

FIG. 13 illustrates an example of configurations of identificationsignals of transmission terminal apparatuses according to the presentembodiment. Here, assume that the number of OFDM symbols usable fortransmission of identification signals is NOFDM and the number ofsubcarriers usable for transmission of identification signals is NSC.Moreover, the number of OFDM symbols used by each transmission terminalto transmit an identification signal is TOFDM, and, in a case of usingOrthogonal Cover Code (OCC) in the time direction, the transmissionterminal uses an OCC sequence having a length of TOCC. Note that the OCCsequence length may be any as long as being a value satisfying1≤TOCC≤TOFDM and information on the OCC sequence length to be used maybe shared in advance by transmission and reception devices. Furthermore,the number of subcarriers to be used by each transmission terminal totransmit an identification signal is assumed to be TSC. In a case ofusing Cyclic Shift (CS) in the frequency direction, the number TCS of CSpatterns is used; and in a case of using Interleaved Frequency DivisionMultiple Access (IFDMA), the number TRF of multiplexing patterns isused. Hence, the number of orthogonal resources for identificationsignals is (NOFDM/TOFDM)×TOCC×(NSC/TSC)×TCS×TRF. FIG. 13 is an exampleof a case that the time-frequency resource in which an identificationsignal can be transmitted is one subframe (NSC=14) and the number ofsubcarriers is NSC, and TOFDM=TOCC=2, the present invention is notlimited to this example. In the case of FIG. 13, assume that NSC=TSC=48and TCS=12, and TRF=2, there exist 336 orthogonal resources.Configuration control information transmitted from the base stationapparatus includes information indicating an orthogonal resource inwhich the identification signal is to be transmitted. Assume that eachof OFDM symbol sets T1 to T7 is defined for two consecutive OFDM symbolsas in FIG. 13 for two OFDM symbols for transmitting an identificationsignal, the index of an OFDM symbol set to be actually used is IT, Xpieces of information of subcarrier sets to be used in a case of NSC>TSCare defined as F1 to FX, the index of the subcarrier set to be actuallyused is IF, the index of OCC sequence to be used is IOCC, the CS patternto be used is ICS, and the multiplexing pattern of the IFDMA to be usedis IRF. In this case, the configuration control information transmittedfrom the base station apparatus includes information uniquely indicating(IT, IF, IOCC, ICS, IRF). The configuration control information may beinformation including only part of (IT, IF, IOCC, ICS, IRF). Note thatthe OFDM symbol set need not be consecutive OFDM symbols and may be acombination such as OFDM symbol #1 and OFDM symbol #8. Moreover, asubcarrier set need not be consecutive subcarriers, and, for example, anintegral multiple of TRF may be defined as a cluster of anidentification signal and clusters of multiple identification signalsmay be inconsecutively used on the frequency axis. Subcarriers S#1 toS#NSC usable for transmission of identification signals may be the sameas or different from the subcarriers for data transmission. In a casethat the subcarriers S#1 to S#NSC are different from the subcarriersusable for transmission of identification signals, only part ofsubcarriers may overlap. The subcarriers S#1 to S#NSC may be the same asor different from the subcarriers used for transmission ofidentification signals. In a case that the subcarriers S#1 to S#NSC aredifferent from the subcarriers to be used for transmission ofidentification signals, only part of subcarriers may overlap. In a casethat the number of terminal apparatuses accommodated by the base stationapparatus exceeds the number of orthogonal resources for theidentification signals, the same orthogonal resources need to beallocated for different terminal apparatuses in an overlapping manner.In this case, transmission terminal apparatuses need to be identified byterminal-apparatus-specific identifiers in addition to orthogonalresources for the identification signals. Specifically, CRC added toeach data signal is subjected to exclusive-OR operation using aterminal-apparatus-specific ID, such as a Cell-Radio Network TemporaryIdentifier (C-RNTI) or SPS C-RNTI. In this manner, a receiving-side basestation apparatus performs exclusive-OR operation on multipleidentifiers and CRC after signal detection using SIC, turboequalization, or the like, and identifies each identifier with no errordetected through CRC, to thereby perform identification of thetransmission terminal apparatus.

FIG. 14 illustrates an example of identification signals and datatransmission of the terminal apparatuses according to the presentembodiment. As illustrated in FIG. 14, data transmission is performedmultiple times in transmission of data in the present embodiment. As aresult, a prescribed quality required for uplink data transmission ofeach terminal apparatus is satisfied. Here, in the known LTE and thelike, each of all the terminal apparatuses performs retransmission ofdata transmission is performed after a prescribed time from datatransmission.

In the present embodiment, to enable channel estimation using eachidentification signal, data is mapped without performing DMRStransmission in OFDM symbols #4 and #11 in a data transmission subframe(UL transmission subframe) in the frame structure in FIG. 5. Hence, thenumber of bits that can be transmitted per transmission opportunityincreases. In the present embodiment, processing by the signalmultiplexing unit 104 in the terminal apparatus in FIG. 9 varies. Thereference signal multiplexing unit 1041 and the reference signalgeneration unit 1042 perform DMRS generation and multiplexing with adata signal. However, in the contention-based (Grant Free) radiocommunication technique, the identification signal and DMRS are shared,and thus the reference signal multiplexing unit 1041 and the referencesignal multiplexing unit 1042 do not perform anything. However, in acase that the terminal apparatus also uses the non-contention-basedradio communication technique, the reference signal multiplexing unit1041 and the reference signal generation unit 1042 perform DMRSgeneration and multiplexing with a data signal, in data transmission inthe non-contention-based radio communication technique. Moreover, in thepresent embodiment, the processing performed by the signal separators205-1 to 205-N in the base station apparatus in FIG. 11 varies. Thereference signal separator 2051 separates DMRS but does not performanything in the contention-based radio communication technique, sincethe identification signal and DMRS are shared. However, in a case thatthe terminal apparatus also uses the non-contention-based radiocommunication technique, the reference signal separator 2051 separatesDMRS in data transmission in the non-contention-based radiocommunication technique.

Each of FIG. 15A and FIG. 15B illustrates an example of an uplink radioframe structure according to a radio communication technique in thepresent embodiment. FIG. 15A is an example in which a subframe fortransmitting an identification signal and a subframe for datatransmission (UL transmission) form one subframe set, and subframe setsare configured as access regions 1 to 5. The base station apparatustransmits configuration control information (S200 in FIG. 3) forallowing, for each terminal apparatus to accommodate, data transmissionin the contention-based radio communication technique in at least one ofaccess regions 1 to 5. Here, transmission permission for access regions1 to 5 may be notified using control information indicating one or moreaccess regions, may be notified using control information indicatingonly one access region, or control information indicating only twoaccess regions, in a bitmap. In this way, the access region(s) in whichthe contention-based radio communication technique can be used islimited for each terminal apparatus. For example, by setting, indifferent access regions, terminal apparatuses in which datatransmission occurs at the same timing, the probability of datatransmission collision can be reduced. Moreover, by setting, indifferent access regions, terminal apparatuses in which orthogonalresources for identification signals overlap, a reduction in accuracy inidentification of transmission terminals due to collision of orthogonalresources for identification signals can be prevented. By the basestation apparatus allowing data transmission in the contention-basedradio communication technique as many access regions as possible fortransmission terminals with high data transmission frequency or withneed of reducing delay time to data transmission, the QoS or the QoE ofeach terminal apparatus can be met.

Meanwhile, FIG. 15B is an example in which an access region isconfigured of multiple subframe sets. FIG. 15B is an example in whichtwo subframe sets are assigned to each of access regions 1 and 2 and onesubframe set is assigned to access region 3. In this case, the number ofterminal apparatuses allowed data transmission in the contention-basedradio communication technique in each of access regions 1 and 2 may beset twice as many as that in access region 3. As another example ofusing access regions 1 to 3, a number of terminal apparatuses areallowed to use access regions 1 and 2, and a few terminal apparatusesrequiring reliability may be allowed to use access region 3.

FIG. 16 illustrates an example of an uplink frame structure according tothe radio communication technique of the present embodiment. In FIG. 16,each access region is limited using frequency resources, and thesmallest frequency resource (e.g., one or more resource blocks, resourceblock groups, or the like) is defined as an access region. In thisexample, F1 to F4 are defined as access regions, and an access region(s)usable in the contention-based radio communication technique isspecified using configuration control information for each terminalapparatus. Note that the subframe sets described with reference to FIG.15A and FIG. 15B may be used simultaneously. For example, consecutivesubframe sets are configured as T1 to T5, and 20 combinations of F1 toF4 and T1 to T5 are configured as access regions, which may be definedaccording to frequency and time. In a case that a usable accessregion(s) is specified for a terminal apparatus, the number of accessregions may be limited to one or may be multiple.

Data transmission is not necessarily needed for the terminal apparatusesaccommodated by the base station apparatus. In view of this, in thepreset embodiment, in the contention-based radio communicationtechnique, the base station apparatus performs, for each terminalapparatus, notification of transmission suspension (deactivation, astate of not being capable of data transmission in the contention-basedradio communication technique) in addition to transmission permission(activation, a state of being capable of data transmission in thecontention-based radio communication technique) in the access region.This reduces the number of terminal apparatuses activated in each accessregion, it is possible for the base station apparatus to reduce, theprobability of data transmission collision probabilistically, whichenables improvement of communication quality. In a case of frequentlyiterating switching of activation and deactivation, the amount ofcontrol information increases by transmitting control information forevery switching. The base station apparatus may notify the cycle ofactivation and deactivation, notify the subframe sets for activation anddeactivation, notify the subframe sets for activation and deactivation,for every frequency resource, or the like, in configuration controlinformation. Activation, deactivation and hopping of the orthogonalresource for the identification signal may be applied simultaneously.

The configuration control information transmitted from the base stationapparatus in the present embodiment will be described. The configurationcontrol information is transmitted in advance as in S200 in FIG. 3. Thisconfiguration control information may include, not only informationindicating the orthogonal resource for transmitting identificationinformation, the frequency resource (frequency position, bandwidth) tobe used for data transmission, Modulation and Coding Scheme (MCS), thenumber of transmissions in a case of performing data transmissionmultiple times, whether or not HARQ is applied, a control value for theclosed-loop of transmission power control, cell-specific andterminal-apparatus-specific target reception, a parameter for fractionaltransmit power control, whether or not DMRS is transmitted in a datatransmission subframe (subframe for UL transmission in FIG. 5), CSpattern α and OCC pattern [w(0), w(1)] of DMRS in a case of transmittingDMRS in the data transmission subframe, whether or not CSI istransmitted, whether or not SRS is transmitted, and/or the like. Notethat the base station apparatus may transmit configuration controlinformation according to the state, capability, and/or QoS of theterminal apparatus. An example of a sequence chart of data transmissionin this case is illustrated in FIG. 17. In FIG. 17, the base stationapparatus transmits configuration control information that does notchange according to the state, capability, and/or QoS of the terminalapparatus (S300). For example, such configuration control informationindicates whether or not HARQ is applied, whether or not CSI istransmitted, whether or not DMRS is transmitted in a data transmissionsubframe, whether or not SRS is transmitted, or the like. Next, theterminal apparatus transmits transmission data and information on theterminal apparatus (S301). For example, the data size and data rate ofthe data to be transmitted from the terminal apparatus, transmissionquality (required packet error rate), a packet loss value, and the likeare transmitted. After the reception of the transmission data and theinformation on the terminal apparatus from the terminal apparatus, thebase station apparatus transmits configuration control informationaccording to the state, capability, and/or QoS of the terminal apparatus(S302). For example, the configuration control information includes afrequency resource (frequency position, bandwidth), MCS, cell-specificand terminal-apparatus-specific target reception, and the like.Moreover, in a case that the terminal apparatus may also includemultiple transmit antennas, the number of transmission layers (ranks),the MCS for each layer (or for each codeword), and precodinginformation. Processing from S201-1 to S202 in FIG. 3 are similar toprocessing in FIG. 3, and thus transmission thereof is omitted.

In the present embodiment, an example of FDD has been described.However, this is also applicable to TDD. Note that whether the terminalapparatus may perform the same data transmission multiple times, and thenumber of transmissions may be notified as QoS from the terminalapparatus or may be determined by the base station apparatus for eachcell.

As described above, in the present embodiment, a DMRS and anidentification signal are shared in the contention-based radiocommunication technique, which enables improvement of the frequencyefficiency. Moreover, by the base station apparatus specifying an accessregion for each terminal apparatus, it is possible to reduce theprobability of data transmission collision, which enables improvement ofcommunication quality. As a result of this, improvement of the receptionquality and improvement of the frequency efficiency of the entire systemare possible, and hence a number of terminals can be efficientlyaccommodated.

Second Embodiment

In a second embodiment of the present invention, an example in which anidentification signal indicating whether or not there is transmissiondata is transmitted, instead of an identification signal for atransmission terminal apparatus, will be described.

In the present embodiment, a configuration example of a terminalapparatus is as illustrated in FIGS. 6, 7, 8, and 9 as in the firstembodiment, and a configuration example of a base station apparatus isas illustrated in FIGS. 10, 11, and 12 as in the first embodiment. Asequence chart of data transmission of the terminal apparatus is as inthe first embodiment, as illustrated in FIG. 3 or 17. Hence, adescription is only given of different processing in the presentembodiment, and a description of similar processing is omitted.

An identification signal is used not for identification of atransmission terminal apparatus but for identification of transmissiondata (whether or not there is transmission data or identification ofpresence of transmission data) in the present embodiment, and thustransmission of the identification signal is performed using the framestructure in FIG. 5. In the present embodiment, in the terminalapparatus, the identification signal multiplexing unit 106 and theidentification signal generation unit 115 in FIG. 6 perform generationand multiplexing of the identification signal for identification of datatransmission, instead of identification of a transmission terminalapparatus. Here, the identification signal multiplexing unit 106 and theidentification signal generation unit 115 select an orthogonal resourcefor an identification signal. In a method of selecting an orthogonalresource for an identification signal, an orthogonal resource may berandomly selected by the terminal apparatus. Regarding a candidate foran orthogonal resource for an identification signal, multiple candidatesmay be notified in configuration control information by the base stationapparatus in a terminal-apparatus-specific manner, multiple candidatesmay be notified through transmission of broadcast information(broadcasting) by the base station apparatus, or the candidate for theorthogonal resource may be predetermined by the terminal apparatus andthe base station apparatus. The terminal apparatus may be notified of anorthogonal resource candidate by a base station apparatus different froma data transmission destination base station apparatus. Moreover, theterminal apparatus may receive, from a base station apparatus differentfrom the data transmission destination base station apparatus,information on a base station apparatus capable of a contention-basedradio communication technique, for example, information such as a cellID, a usable frequency or bandwidth, or an orthogonal resource of anidentification signal, and use the contention-based radio communicationtechnique at the time when detection of a synchronization signal,broadcast information, or the like of a base station apparatus capableof using the contention-based radio communication technique is enabled.

In the present embodiment, the base station apparatus performs, in theidentification signal separators 203-1 to 203-N and the transmissionterminal identification unit 211 in FIG. 10, separation and detection ofan identification signal for identification that data has been received,instead of identification of a transmission terminal apparatus. Atransmission terminal apparatus cannot be uniquely identified even in acase that an identification signal is detected, and thus identificationinformation on a transmission terminal apparatus is included in a datatransmission subframe (UL transmission subframe). In a case of selectinga contention-based radio communication technique in the trafficmanagement unit 114 in FIG. 6, the terminal apparatus includes anidentifier of the terminal apparatus, in a data bit sequence. Theidentifier may be C-RNTI, may be assigned in advance using configurationcontrol information, or may be another terminal-apparatus-specificinformation. In a case that terminal-apparatus-specific identificationinformation is included in a data signal, the base station apparatuschecks that there is no error bit through CRC in the decoding units2065-1 to 2065-U in FIG. 12, then acquires the identifier of a terminalapparatus included in the data bit sequence, and performs identificationof the transmission terminal apparatus. The decoding units 2065-1 to2065-U may input terminal-apparatus-specific identification informationin the obtained information bit sequence, into the transmission terminalidentification unit 211. In a case of transmitting control information,such as ACK/NACK to the transmission terminal apparatus, the informationon the identified transmission terminal apparatus is output to thecontrol information generation unit 208. Subsequent processing issimilar to that in the first embodiment, and hence a description thereofis omitted.

A description will be given of another example of a method ofidentifying a transmission terminal apparatus according to the presentembodiment. The base station apparatus identifies whether or not thereis transmission data, by using an identification signal and thenperforms detection of a signal in the signal detection unit 206. Thedecoding units 2065-1 to 2065-U obtain a bit sequence after errorcorrection decoding, then performs exclusive-OR operation on the CRC andC-RNTI, and then checks whether or not there is any error bit. Here, theC-RNTI is terminal-apparatus-specific information and the transmissionterminal apparatus cannot be identified based on an identificationsignal in the present embodiment, and thus the C-RNTI to be used cannotbe identified. In view of this, the decoding units 2065-1 to 2065-U holdinformation (C-RNTI) on a terminal apparatus having possibility ofperforming data transmission in the contention-based radio communicationtechnique and check whether or not there is any error bit in a result ofan exclusive-OR operation of each of all the held C-RNTI and the CRC. Inother words, the base station apparatus can identify the terminalapparatus using the C-RNTI for which no existence of any error bit isconfirmed through CRC, as the terminal apparatus that has transmittedthe data.

In the above-described way, the base station apparatus need not makenotification of the orthogonal resource of the identification signal tobe used by the terminal apparatus for data transmission throughconfiguration control information. Meanwhile, the terminal apparatus mayuse any orthogonal resource. In the present embodiment, controlinformation relating to another data transmission may be transmitted bytransmission of broadcast information (broadcasting), and in this case,transmission of configuration control information in S200 in thesequence chart in FIG. 3 need not transmit terminal-specific controlinformation but may use a broadcast channel. This means that, in a caseof making notification of an orthogonal resource of identificationinformation as broadcast information, any terminal apparatus capable ofreceiving the broadcast information uses the notified orthogonalresource of the identification signal and that the orthogonal resourcecan be shared and used by a number of terminal apparatuses.

In this case, the terminal apparatus that has acquired an identifier atthe time of first establishment of a connection with a base stationapparatus can discover the base station apparatus, based on asynchronization signal or a reference signal of the base stationapparatus, and perform, after reception of broadcast channelinformation, data transmission (contention-based radio communicationtechnique) without transmission and/or reception ofterminal-apparatus-specific control information. Acquisition of theidentifier may not be performed by the base station apparatus to performdata transmission. For example, in a case that there exist a macro basestation apparatus with a large coverage and a small base stationapparatus with a small coverage, it is possible for the terminalapparatus to acquire an identifier at the time of establishment of aconnection with the macro base station apparatus and to perform datatransmission or the like without transmission and/or reception ofterminal-apparatus-specific control information after entering thecoverage of the small base station apparatus.

Note that the terminal apparatus may notify the base station apparatusof whether the terminal apparatus performs the same data transmissionmultiple times and the number of transmissions, as QoS or may bedetermined by the base station apparatus for each cell. The terminalapparatus may be notified in advance of an access region for whichtransmission is allowed as in the first embodiment, and the terminalapparatus may select an orthogonal resource for an identification signalin the access region for which transmission is allowed as in the presentembodiment and transmit the identification signal and a data signal.Information on the access region for which transmission is allowed maybe information on a time domain, such as information on a subframe setor an OFDM symbol, may be information on a frequency resource, or may bea resource defined by both time and frequency.

As described above, in the present embodiment, in the contention-basedradio communication technique, a signal for identification of atransmission terminal apparatus is included in a data bit sequence, andthe terminal apparatus can freely determine an orthogonal resource to beused for transmission of an identification signal of data transmission.Hence, in a case of acquiring an identifier in advance, by discovering abase station apparatus and receiving information on a broadcast channel,the terminal apparatus can perform data transmission withouttransmission and/or reception of terminal-apparatus-specific controlinformation. Consequently, the amount of control information can bereduced, the improvement of the frequency efficiency of the entiresystem is possible, and a number of terminals can be efficientlyaccommodated.

A program running on a device according to the present invention mayserve as a program that controls a Central Processing Unit (CPU) and thelike, and causes a computer to operate in such a manner as to realizethe functions of the embodiments according to the present invention.Programs or the information handled by the programs are temporarilystored in a volatile memory, such as a Random Access Memory (RAM), anon-volatile memory, such as a flash memory, a Hard Disk Drive (HDD), oranother storage device system.

Note that a program for implementing the functions of any of theembodiments relating to the present invention may be recorded on acomputer readable recording medium. The functions may be implemented bycausing a computer system to read and execute the program recorded onthe recording medium. It is assumed that the “computer system” hererefers to a computer system built into the devices, and the computersystem includes an operating system and hardware components such as aperipheral device. Furthermore, the “computer-readable recording medium”may be any of a semiconductor recording medium, an optical recordingmedium, a magnetic recording medium, a medium dynamically holding aprogram for a short time, or another computer readable recording medium,or the like.

Furthermore, each functional block or various characteristics of thedevices used in the above-described embodiments may be mounted orperformed on an electric circuit, for example, an integrated circuit ormultiple integrated circuits. An electric circuit designed to performthe functions described herein may include a general-purpose processor,a digital signal processor (DSP), an application specific integratedcircuit (ASIC), a field programmable gate array (FPGA), or otherprogrammable logical devices, discrete gates or transistor logic,discrete hardware components, or a combination thereof. Thegeneral-purpose processor may be a microprocessor, or may be a processorof known type, a controller, a micro-controller, or a state machine. Theabove-mentioned electric circuit may be constituted of a digitalcircuit, or may be constituted of an analog circuit. Furthermore, in acase that with advances in semiconductor technology, a circuitintegration technology appears that replaces the present integratedcircuits, it is also possible for the present invention to use anintegrated circuit based on the technology.

Note that the invention of the present patent application is not limitedto the above-described embodiments. In the embodiments, devices havebeen described as an example, but the invention of the presentapplication is not limited to these devices, and is applicable to aterminal apparatus or a communication device of a fixed-type or astationary-type electronic apparatus installed indoors or outdoors, forexample, an AV apparatus, a kitchen apparatus, a cleaning or washingmachine, an air-conditioning apparatus, office equipment, a vendingmachine, and other household apparatus.

The embodiments of the present invention have been described in detailabove referring to the drawings, but the specific configuration is notlimited to the embodiments and includes, for example, an amendment to adesign that falls within the scope that does not depart from the gist ofthe present invention. Furthermore, various modifications are possiblewithin the scope of the present invention defined by claims, andembodiments that are made by suitably combining technical meansdisclosed according to the different embodiments are also included inthe technical scope of the present invention. Furthermore, aconfiguration in which a constituent element that achieves the sameeffect is substituted for the one that is described in any of theembodiments is also included in the technical scope of the presentinvention.

The present international application claims priority based on JP2016-077077 filed on Apr. 7, 2016, and the entire content of JP2016-077077 is incorporated in the present international application byreference.

DESCRIPTION OF REFERENCE NUMERALS

-   -   10 Base station apparatus    -   20-1 to 20-Nm Terminal apparatus    -   101 Error correction coding unit    -   102 Modulating unit    -   103 Transmit signal generation unit    -   104 Signal multiplexing unit    -   105 IFFT unit    -   106 Identification signal multiplexing unit    -   107 Transmit power controller    -   108 Transmission processing unit    -   109 Transmit antenna    -   110 Receive antenna    -   111 Radio receiving unit    -   112 Control information detection unit    -   113 Transmission parameter storage unit    -   114 Traffic management unit    -   1030 Phase rotation unit    -   1031 DFT unit    -   1032 Signal assignment unit    -   1033 Phase rotation unit    -   1034 Interleaving unit    -   1041 Reference signal multiplexing unit    -   1042 Reference signal generation unit    -   1043 Control information multiplexing unit    -   1044 Control information generation unit    -   201-1 to 201-N Receive antenna    -   202-1 to 202-N Reception processing unit    -   203-1 to 203-N Identification signal separator    -   204-1 to 204-N FFT unit    -   205-1 to 205-N Signal separator    -   206 Signal detection unit    -   207 Channel estimation unit    -   208 Control information generation unit    -   209 Control information transmitting unit    -   210 Transmit antenna    -   211 Transmission terminal identification unit    -   2051 Reference signal separator    -   2052 Control information separator    -   2053 Assignment signal extraction unit    -   2054 Control information detection unit    -   2061 Cancellation processing unit    -   2062 Equalization unit    -   2063-1 to 2063-U IDFT unit    -   2064-1 to 2064-U Demodulation unit    -   2065-1 to 2065-U Decoding unit    -   2066-1 to 2066-U Symbol replica generation unit    -   2067 Soft replica generation unit

1.-8. (canceled)
 9. A terminal apparatus configured to communicate witha base station apparatus, the terminal apparatus comprising: controlinformation reception circuitry configured to receive first radioresource control (RRC) information and second RRC information through ahigher-layer signalling, and monitor a physical downlink control channel(PDCCH) candidate with a downlink control information (DCI) format, andtransmission circuitry configured to perform a first uplink datatransmission or a second uplink data transmission, wherein the first RRCinformation includes first radio resource information, a modulation andcoding scheme (MCS) information, and a precoding and number of layers,the second RRC information includes periodicity, the DCI includes secondradio resource information, in a case where the control informationdetection circuitry receives the first RRC information and the secondRRC information, the transmission circuitry performs the first uplinkdata transmission by using the first RRC information and the second RRCinformation, and in a case where the control information detectioncircuitry does not receive the first RRC information and does receivethe second RRC information, the transmission circuitry performs thesecond uplink data transmission by using the second RRC information andthe DCI.
 10. A base station apparatus configured to communicate with aterminal apparatus, the base station apparatus comprising: transmissioncircuitry configured to transmit first radio resource control (RRC)information and second RRC information through a higher-layersignalling, and transmit a physical downlink control channel (PDCCH)with a downlink control information (DCI) format, and receptioncircuitry configured to perform a reception of first uplink data or areception of second uplink data, wherein the first RRC informationincludes first radio resource information, a modulation and codingscheme (MCS) information, and a precoding and number of layers, thesecond RRC information includes periodicity, the DCI includes secondradio resource information, in a case where the transmission circuitrytransmits the first RRC information and the second RRC information, thereception circuitry performs the reception of the first uplink datatransmitted based on the first RRC information and the second RRCinformation, and in a case where the transmission circuitry does nottransmit the first RRC information and does transmit the second RRCinformation, the reception circuitry performs the reception of thesecond uplink data transmitted based on the second RRC information andthe DCI.
 11. A communication method for a terminal apparatus configuredto communicate with a base station apparatus, the communication methodcomprising: receiving first radio resource control (RRC) information andsecond RRC information through a higher-layer signalling, and monitoringa physical downlink control channel (PDCCH) candidate with a downlinkcontrol information (DCI) format, and performing a first uplink datatransmission or a second uplink data transmission, wherein the first RRCinformation includes first radio resource information, a modulation andcoding scheme (MCS) information, and a precoding and number of layers,the second RRC information includes periodicity, the DCI includes secondradio resource information, in a case of receiving the first RRCinformation and the second RRC information, performing the first uplinkdata transmission by using the first RRC information and the second RRCinformation, and in a case of not receiving the first RRC informationand receiving the second RRC information, performing the second uplinkdata transmission by using the second RRC information and the DCI.
 12. Acommunication method for a base station apparatus configured tocommunicate with a terminal apparatus, the communication methodcomprising: transmitting first radio resource control (RRC) informationand second RRC information through a higher-layer signalling, andtransmitting a physical downlink control channel (PDCCH) with a downlinkcontrol information (DCI) format, and performing a reception of firstuplink data or a reception of second uplink data, wherein the first RRCinformation includes first radio resource information, a modulation andcoding scheme (MCS) information, and a precoding and number of layers,the second RRC information includes periodicity, the DCI includes secondradio resource information, in a case of transmitting the first RRCinformation and the second RRC information, performing the reception ofthe first uplink data transmitted based on the first RRC information andthe second RRC information, and in a case of not transmitting the firstRRC information and transmitting the second RRC information, performingthe reception of the second uplink data transmitted based on the secondRRC information and the DCI.